Macrocystalline watch dial

ABSTRACT

A watch dial has an outer surface consisting of metal crystals large enough to be seen by the naked eye. Such crystals are formed by annealing of the metal and may have been treated by etching, coloring, dyeing, coating, oxidation or sulphuration.

United States Patent [1 1 Kasai et al.

[451 Feb. 4, 1975 1 1 MACROCYSTALLINE WATCH DIAL [75] Inventors: Kazutomo Kasai, Shimosuwa-machi; Shuzo Koizumi, Suwa, both of Japan [73] Assignee: Kabushiki Kaisha Suwa Seikosha,

Tokyo, Japan [22] Filed: Aug. 21, 1973 [21] App]. No.: 390,290

[52] U.S. C1. 58/127 R, 29/182, 29/195 M, 29/195 Y, 29/196, 29/199,117/107,148/31.5 [51] Int. Cl. G04b 19/10 [58] Field of Search 58/127 R; 117/107; 25/200; 148/315, 31; 175/123 R, 175 R; 204/153, 35 R; 29/195 M, 195 Y, 196, 199

[56] References Cited UNITED STATES PATENTS 2,941,930 6/1960 Mostovych et a1 204/35 R X Shibanai 58/127 R Pond 148/115 A Primary ExaminerL. Dewayne Rutledge Assistant Examiner-Arthur J Steiner Attorney, Agent, or Firm-Blum Moscovitz Friedman & Kaplan [57] ABSTRACT 11 Claims, No Drawings MACROCYSTALLINE WATCH DIAL BACKGROUND OF THE INVENTION In recent years, in addition to the principal function of showing the time correctly, watches have become regarded more and more as decorative accessories or costume jewelry. A particularly important part of a watch regarded in this way is the watch dial. In general, colored watch dials are preferred to those of conventional colors such as the yellow of gold or the white of silver.

Where color has been used to enhance the appearance of watch dials, solid colors have usually been used. Consequently, the effect, while pleasant, has not been as striking as might be. Color patterns have been used to some extent but these have been distracting to the eye, and of relatively limited attractiveness.

In view of the extremely competitive market situation with respect to watches, any enhancement of the appearance of the watch dial can contribute markedly to an increase in sales.

SUMMARY OF THE INVENTION In a watch dial, at least the outer surface thereof consists essentially of a metal. After heating in an atmosphere inert to the particular metal, as well as to the substance of which the watch dial is made, crystals of the metal are formed which are large enough to be seen by the unaided eye. In general, the crystals are polished and etched, as by acid or electrolytic anodization, as a result of which the crystal pattern becomes evident. The dial, in final form, is lacquered for protection and has indicia marked thereon.

Accordingly, an object of the present invention is a watch dial, at least the surface of which consists essentially of crystals large enough to be seen by the unaided eye.

Another object of the present invention is a watch dial of improved appearance having a macrocrystalline structure visible to the unaided eye.

A further object of the present invention is a watch dial of improved appearance wherein macrocrystals have been up-graded in appearance by polishing, etching, oxidation, dyeing, or sulphuration.

Yet another object of the present invention is a process for manufacturing a watch dial of improved appearance by forming macrocrystals.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the article possessing the features, properties, and the relation of elements, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As is well known, metals, whether elementary or alloys, display various types of characteristic crystal patterns when properly etched. In general, the size of the crystals is such that the pattern is not visible to the unassisted eye, making it necessary to use a low-power microscope for observation or study of the pattern. This process has been in use for years as a means of identifying metals with respect to their composition and as an indication of treatment to which they may have subjected.

In order to make such patterns visible to the unassisted eye, it is necessary that the crystals be enlarged. An example ofthe way in which this can be done is provided by 70-30 brass which may be employed in an embodiment of the present invention. The crystals of brass in this composition when heated at 850C for l0 hours are substantially enlarged so that when polished. the crystal pattern becomes quite visible. It should be noted that the temperature of heat treatment is below the melting point of the material. Consequently. such heat treatment may appropriately be termed annealing.

In the embodiment presented above. the entire dial may be of brass or just the outer surface may be of this material. The brass may be applied to a suitable substrate, the only requirement being that the substrate have a melting point at least as high as that of the brass. Where the outer surface is a layer on a substrate, the layer may be applied by electrodeposition or by vacuum evaporation or by sputtering. Another method is to make the substrate and the outer surface as a bimetal or a clad metal.

After annealing and polishing the surface of a watchdial in accordance with the present invention, the crystal pattern may be over-plated with silver or gold. The crystal pattern becomes very evident as the result of minute differences in the way the silver or gold is deposited on the surfaces of the crystals themselves and at the interfaces. Where the plating is of silver it is desirable that lacquer be applied over same to prevent corrosion.

The polishing process generally consists of a combination of mechanical polishing with fine abrasives and etching with acids, but either mechanical or chemical polishing with acid etchants may be used alone. A preferred etchant is 5 percent nitric acid.

The crystal pattern may also be enhanced by oxidation of metals or evaporation of oxides onto the surface. Where oxides are evaporated characteristic colors are obtained. For instance, tungsten oxide when evaporated gives a deep blue color and the color changes in accordance with the angle of light falling on the surface. Surprisingly where an inorganic glass is evaporated onto the surface of the dial, the dial appears more metallic.

An orange color may be imparted to a brass plate if it is soaked in an alkaline solution of copper carbonate. Appropriate conditions are the use of a solution containing 25g of NaOH and 50g of CuCO in contact with the surface for a few minutes at C.

A film of chromic oxide may be formed on the surface of the dial by conventional procedure. It can subsequently be dyed blue or red using organic dyestuffs.

Clear lacquer is a preferred means of preventing corrosion. However, colored lacquer may also be used to obtain special effects.

Chromium may be evaporated onto the surface ofthe dial, after which heating at 700C in a controlled oxidizing atmosphere results in the production of a green color. Alternatively, silicon may be evaporated onto the surface and then oxidized to a controlled extent, as the result of which interference colors such as a bright blue may be obtained.

Where the crystalline surface has been plated with silver, this may be sulphurized to produce an aged effect, which can then be protected by lacquering.

An excellent effect is obtained by annealing brass as described above until a macrocrystalline pattern is formed, then electroplating with silver to a thickness of about 2p. and covering with clear lacquer to protect the silver from corrosion. In comparison with conventional silver-plated dials, this particular construction is extremely metallic in appearance and due to the variation in color caused by light scattering seems to be 3- dimensional.

Evaporation of cobalt to produce a film of about la in thickness on a copper dial which has been annealed to make it macrocrystalline and subsequent treatment for 3 hours at 850C in an atmosphere wherein the oxygen pressure is held at a low level but not so low that oxidation cannot take place, yields a characteristic and distinct blue color. The color tone is particularly attractive due to the fact that the dial shows the crystalline pattern of the copper.

A brass plate, annealed as described above may be coated with tin by immersion in the molten metal. A coating thickness of about 130p. is suitable. The coating is then mechanically polished and is etched by electrolysis in perchloric acid and acetic acid solution. An attractive pattern may also be obtained without prior annealing of the brass.

A further embodiment of the present invention is produced by mixing 93 parts by weight of iron and 7 parts by weight of copper, both materials being in the size range of 100 200a, pressing into the form of a disc and sintering for 4 hours at about [000C in an inert atmosphere. The surface is then mechanically polished after which it is etched with dilute HCl. The iron grains will be from 0.3 to 0.8 mm in size. A dial prepared in this way can then be overcoated in any of the ways already noted.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and, since certain changes may be made in carrying out the above process and in the article set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

What is claimed is: l

l. A watch dial having an outer face consisting essentially of metal crystals large enough to be visible to the unassisted eye, said metal selected from the group consisting of iron, tin, copper and alloys thereof.

2. The watch dial as defined in claim I wherein said crystals are in the annealed state.

3. The watch dial as defined in claim 1, wherein said crystal face is in the annealed, etched and polished state.

4. The watch dial as defined in claim I wherein said face further comprises indicia thereon and a lacquer coating on said face and said indicia.

5. The watch dial as defined in claim 1 wherein said metal crystals are embedded in a metallic binder.

6. The watch dial as defined in claim 5, wherein said metallic binder is of a contrasting color with respect to said crystals.

7. The watch dial as defined in claim 1 wherein said outer surface has thereon a metallic oxide coating of thickness such that the pattern of said large metal crystals is visible to the unassisted eye.

8. The watch dial as defined in claim 1, wherein said outer face has thereon a coating of a member selected from the group consisting of chromium, silicon, tungsten and glass.

9. The watch dial as defined in claim 1, wherein said outer face is in the dyed state.

10. The watch dial as defined in claim 1, wherein said outer face has thereon a coating of a sulfide of at least one of said members of said group.

11. The watch dial as defined in claim 1, wherein said outer face has thereon a plated metal selected from the group consisting of silver and gold, said plated metal being ofa thickness such that the pattern of said metal crystals is visible to the unassisted eye.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,863439 Dated February 4, 1975 Kazutomo Kasai and Shuzo Koizumi It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Please insert the following at the appropriate point on page 1 of the above-identified patent:

[30] Foreign Application Priority Data August 23 1972 Japan 83648/72 September 7, 1972 Japan 8992 2/72 Signed and sealed this rOth day of June 1975..

(SEAL) Attest:

C. MARSHALL DANN Commissioner of Patents and Trademarks RUTH C. MASON Attesting Officer UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 3,863,439 a d February 4, 1975 Patent No.

Kazutomo Kasai and Shuzo Koizumi It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Please insert the following at the appropriate point on page 1 of the above-identified patent:

[30] Foreign Application Priority Data August 23 19-72 Japan 83648/72 September 7, 1972 Japan 8992 2/72 Signed and sealed this IOth day of June 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks 

2. The watch dial as defined in claim 1 wherein said crystals are in the annealed state.
 3. The watch dial as defined in claim 1, wherein said crystal face is in the annealed, etched and polished state.
 4. The watch dial as defined in claim 1 wherein said face further comprises indicia thereon and a lacquer coating on said face and said indicia.
 5. The watch dial as defined in claim 1 wherein said metal crystals are embedded in a metallic binder.
 6. The watch dial as defined in claim 5, wherein said metallic binder is of a contrasting color with respect to said crystals.
 7. The watch dial as defined in claim 1 wherein said outer surface has thereon a metallic oxide coating of thickness such that the pattern of said large metal crystals is visible to the unassisted eye.
 8. The watch dial as defined in claim 1, wherein said outer face has thereon a coating of a member selected from the group consisting of chromium, silicon, tungsten and glass.
 9. The watch dial as defined in claim 1, wherein said outer face is in the dyed state.
 10. The watch dial as defined in claim 1, wherein said outer face has thereon a coating of a sulfide of at least one of said members of said group.
 11. The watch dial as defined in claim 1, wherein said outer face has thereon a plated metal selected from the group consisting of silver and gold, said plated metal being of a thickness such that the pattern of said metal crystals is visible to the unassisted eye. 